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AMD put the 64-bit Opteron processor's RAM controller right on the die, eliminating the front-side bus.

Suddenly, everything about 64-bit computing is new again. In some form, 64-bit processors designed for proprietary operating systems have been in data centers for years. But the recent debut of the Opteron microprocessor chip from Advanced Micro Devices Inc. of Sunnyvale, Calif., to be followed this summer by an upgraded Itanium 2 from Intel Corp., promises to ratchet up the pressure to switch enterprise applications away from the 32-bit track. That's because devices priced in the PC server range will have 64-bit capability.

Database performance stands to be one of the chief beneficiaries of 64-bit processing, although the new chip sets could well find their way into other parts of the enterprise.

The Opteron architecture will give data centers a natural migration path, said Rick Indyke, AMD's federal business manager. The processor will allow agencies to run 32-bit operating systems and applications today and later switch to a 64-bit environment without purchasing new hardware.

The Opteron, which was code-named SledgeHammer during development, runs both 32- and 64-bit applications without the need for recompiling or emulation.

AMD uses a fabrication process in which Opteron's smallest features measure 0.13 microns across. Available at clock speeds of 1.4 GHz to 1.8 GHz, the new processor uses silicon-on-insulator technology to reduce electrical leaks from all those tiny transistors packed so closely together.

Unlike 32-bit processors, Opteron can address more than 4G of RAM at a time, said David Jessel, a design engineer and business development manager at AMD's Boston Design Center. That freedom applies, however, only to native 64-bit software.

An Opteron server running a 32-bit operating system will still face that 4G limit, Jessel said. When a customer upgrades that server to a 64-bit OS, any 64-bit applications running on the server can address up to 1T of physical RAM and 256T of virtual RAM.

AMD has dubbed the Opteron's architecture the x86-64 architecture because it consists of a set of extensions to the 32-bit x86 architecture that dates back to the mid-1980s.

In contrast, Intel's Itanium 2 processor uses an entirely different architecture from x86, called explicitly parallel instruction computing. It relies on a separate set of circuits to run 32-bit applications.

At the moment, Operton seems to be geared toward two- and four-way servers, while Itanium is made for eight-way and up systems, said Gordon Haff, senior analyst with Illuminata Inc. of Nashua, N.H.

Huff said he expects a fairly smooth, if lengthy, transition to 64-bit computing, noting a similar transition from 16-bit to 32-bit. With the chips available, he said, 'you are going to reach a point where there's no additional cost to going to 64-bit, and then that will become the standard.'

Besides the Opteron's native support for both 32- and 64-bit applications, AMD officials are touting two other innovations. To increase the chip's bandwidth, AMD put the Opteron's RAM controller right on the die and included the so-called HyperTransport interconnect technology.

In typical systems today, the front-side bus becomes a bottleneck, Jessel said. By eliminating the front-side bus, AMD gave the Opteron a maximum bandwidth of 5.3 gigabytes/sec.

AMD's scheme for assigning three-digit model numbers to the Opteron chips reflects the company's ongoing crusade to dethrone clock speed as the most important measure of a processor's performance.

The first digit shows the number of other chips the processor is designed to work with, Jessel said. The second and third digits depict relative performance within the series.

For example, the Opteron 2xx series of processors was designed for two-way servers. Within that series, the Opteron 242, 244 and 246 are ranked in ascending order of performance.

Early adopters

The new Opteron CPU has drawn support from both Microsoft Corp. and the Linux community, Jessel said. At the LinuxWorld January conference in New York, vendors demonstrated IBM DB2, Oracle9i and Computer Associates Inc.'s Ingres databases running on Opteron systems.

SuSE Inc. of Oakland, Calif., already offers a version of its SuSE Enterprise Server 8 for the AMD64 architecture, list-priced at $448 per CPU. Competitor Red Hat Inc. of Raleigh, N.C., plans to release an Opteron version of its Linux Enterprise Server this fall.

Microsoft is developing a 64-bit version of its just-announced Microsoft Windows Server 2003 for a beta release this summer.

Einux Inc. of Milpitas, Calif., has announced blade servers that use Opteron CPUs. And Cray Inc. of Seattle is building for the Energy Department's Sandia National Laboratories a huge supercomputer, dubbed Red Storm, that will use more than 10,000 Opterons upon its completion in 2004.

Handling large chunks of data in memory yields better database performance than storing those chunks on disk, Indyke said. He predicted that huge databases might well be the so-called 'killer app' for 64-bit computing.

Intel Corp. has a road map for its IA-64 architecture that extends to 2005, according to Intel spokeswoman Barbara T. Grimes.

This summer, an upgraded version of the Itanium 2 processor, code-named Madison, will debut with a clock speed of 1.5 GHz and 6M of Level 3 cache. The CPU will be Intel's first product with 0.13-micron-sized transistors.